VPT 421: Veterinary Toxicology (2+0)

MECHANISM OF ACTION

• AFB₁ binds to nuclear DNA and decreases synthesis of RNA and hence decreases enzymes and protein. AFB₁ also binds to endoplasmic steroidal binding sites and cause ribosomal disaggregation.
• Most of the toxicity is due to macromolecular binding.
• Biochemical changes secondary to cytotoxic actions of aflatoxins include increased SGOT, SGPT and alkaline phosphatase, isocitric dehydrogenase and bilirubin.
• There is decrease in serum protein, NPN and urea.
• Synthesis of clotting proteins is also inhibited by aflatoxins. This is one of the basis for harmorrhagic lesions encountered at necropsy.
• In the artificial rumen system, there is decreased cellulose digestion, reduced volatile fatty acid formation and inhibition of proteolysis.